The present invention relates to a method of solubilizing a compound in a medium such as a lubricating composition.
The use of antioxidants as stabilizing materials for lubricant compositions employed with synthetic fibers is known in the art as a means to increase the thermal stability of the lubricant.
However, as process speeds for manufacturing these synthetic fibers have increased, the need for even greater thermal stability of the lubricant has become evident. Improved thermal stability would be effective in reducing the excessive volatility which is present at high temperature points within, for example, the drawing and heat setting processes.
In addition, a lubricant composition having a very high thermal stability would remain fluid at these high temperature process points. Accordingly, if the lubricant is sufficiently stable, any lubricant accumulation occurring at these points will be removed by the continuous wiping action as the fibers are processed. As a result, maintenance costs could be reduced and fiber quality could also be improved because deleterious frictional changes could be effectively eliminated.
As was previously noted, antioxidants are commonly used to enhance the thermal stability of lubricants. However, the need for even greater thermal stability necessitates very high concentrations of antioxidants in lubricant formulations.
Moderate levels of antioxidant can be achieved with compositions such as butylated hydroxytoluene (BHT). Unfortunately, BHT and similar antioxidants have substantial volatility at temperatures used to manufacture and process synthetic fiber. Consequently, this class of antioxidants volatilize rapidly and fail to prevent oxidation.
Other known phenolic antioxidants such as Irganox 1010 which have low volatility also have limited solubility in lubricant formulations. As a result, the requisite high antioxidant concentration cannot be effectively attained.
Thus, the need still exists for a method of increasing the solubility of compounds such as antioxidants in medium in which the compound have only limited solubility, i.e., lubricant compositions.
Accordingly, it is an object of the present invention to provide a method for solubilizing compounds in a medium.
It is a further object to provide a thermally stable lubricant/surfactant composition containing antioxidant groups.
It is still a further object of the present invention to provide lubricant/surfactant compositions which have antioxidant moieties covalently bonded into their structures in order to avoid excessive volatility as well as problems associated with limited solubility.